THE ANSWER OF REDOX REACTION QUIZ Part II

QUIZ FOR YOU

1.      When the Cr⁶⁺ species is converted into Cr³⁺ ions the chromium is being ….

a.       reacted                             

b.      decayed

c.       reduced                            

d.      oxidized

e.       neutralized

2.      When iodide ions are converted into iodine, it is being ….

a.       reduced                            

b.      oxidised   

c.       decayed                            

d.      atomized

e.       neutralized

3.      The equations below which classified as reduction(s) is (are) ….

(1) PbO(s) + C(s) à Pb(s) + CO(g)

            (2) Cl₂(g) + H₂(g) à 2HCl(g)

            (3) Na⁺(l) + e à Na(l)

a.       (1)

b.      (1) and (2)

c.       (1) and (3)

d.      (2) and (3)

e.       (1), (2), and (3)                 

4.      The photosynthesis’ reaction: 6CO₂ + 6H₂O à C₆H₁₂O₆ + 6O₂  The wrong statement about this reaction is ….

a.       carbon dioxide is oxidized       

b.      oxidation occurs when hydrogen is lost

c.       reduction occurs when hydrogen is gained

d.      water loses its hydrogen to carbon dioxide

e.       carbon dioxide gains hydrogen from water

5.      In covalent bonds electrons will shift toward the more electronegative element. Water is formed by the following reaction: 2H₂  +  O₂  à  H₂O. In the water molecule electrons shift away from the hydrogen atoms (oxidized) and toward the oxygen atom (reduced). The correct answer which relates to the information above is ….

a.       hydrogen is oxidized       

b.      there is a transferring electron

c.       oxygen is a reducing agent

d.      hydrogen is a oxidizing agent

e.       there is an ionic reaction

6.      Examples of common redox reactions include all the processes below, except ….

a.       rusting of sulfur               

b.      cellular respiration

c.       any burning reaction

d.      any oxidation of a metal

e.       oxidizing of food in our cells

7.      When a substance is oxidized, it ….

a.       loses protons

b.      gains protons

c.       acts as an oxidizing agent

d.      acts as a reducing agent               

8.      Oxidizing agent is the substance which takes the electrons from another substance causing it to be oxidized. It is the substance which is reduced in a redox reaction. The correct oxidizing agent from the rusting of iron is ….

a.       iron                        d. oxygen         

b.      rust                        e. water

c.       salt

9.      Reducing agent is the substance which gives the electrons to cause another substance to be reduced. It is the substance which is oxidized in a redox reaction. The correct reducing agent from the forming ionic compound of barium chloride is ….

a.       barium atoms                    

b.      chlorine molecules

c.       barium chloride

d.      barium ions

e.       chloride ions

10.  Which statement correctly describes a redox reaction?

a.       The oxidation half-reaction and the reduction-half reaction occur simultaneously.                    

b.      The oxidation half-reaction occurs before the reduction half reaction

c.       The oxidation half-reaction occurs after the reduction half-reaction

d.      The oxidation half-reaction occurs spontaneously but the reduction half-reaction does not

11.  Which quantities are conserved in all oxidation-reduction reactions?

a.       charge, only

b.      mass only

c.       volume only

d.      both charge and mass                   

e.       neither charge and mass

12.  Given the reaction:
    2Li(s) + Cl₂(g) à 2LiCl(s)
As the reaction takes place, the Cl₂(g) will

a.       gain electrons       

b.      lose electrons

c.       gain protons

d.      lose protons.

13.  The following processes which the reactant oxidazed is ....

a.       Cu²⁺           à        Cu      

b.      NO₃^—        à        NO₂

c.       Fe³⁺           à        Fe²⁺    

d.      MnO₂        à        Mn²⁺

e.       Cr³⁺           à        Cr₂O₇²    

14.  The following species that act as a reductant is

KMnO₄ + H₂SO₄ + Fe à K₂SO₄ + MnSO₄ + Fe₂(SO₄)₃ + H₂O

a.       KMnO₄                      

b.      H₂SO₄

c.       Fe             

d.      MnSO₄

e.       Fe₂(SO₄)₃

15.  Corrosion is faster in the presence of an acid or a salt because these are ….

a.       ionic compounds

b.      weak electrolytes

c.       nonelectrolytes

d.      couldn’t conduct electricity

e.       make electron transfer easier  

16.  One of the following equations which can not classified as redox reaction is ....

a.       2 H₂ + O₂ à 2 H₂O

b.      Cu + Cl₂ à CuCl₂

c.       Fe + 2 HCl à FeCl₂ + H₂

d.      2 HCl + CaCO₃ à CaCl₂ + H₂O + CO₂

e.       MnO₂ + 2 HCl à MnCl₂ + H₂O + Cl₂

17.  The corrosion of iron is an oxidation process which occurs by one of the two following reactions:            

2Fe   +  O₂  +  2 H₂O  à  2 Fe(OH)₂

4Fe(OH)₂  + O₂ + 2H₂Oà4 Fe(OH)₃

The iron hydroxide will then oxidize in air to form rust (Fe₂O₃). This process can be prevented by surface protection, covering the iron with ... to prevent the iron from coming into contact with water or air.

(1)   paint

(2)   oil

(3)   plastic

The correct answer is (are) ….

a.       (1)

b.      (2)

c.       (3)

d.      (1) and (2)

e.       (1), (2), and (3)     

18.  Cl₂ + NaOH à NaCl + NaClO₃ + H₂O. The oxidation number of chlorine changes from ....

a.       0 to –1

b.      0 to +5

c.       0 to -1 and +5                  

d.      -1 to +5

e.       -1 to 0 and +5

19.  The element that act as oxidant and reductant in the reaction below is ….

Br₂ + KOH à NaBr + NaBrO + H₂O

a.       Br₂                        

b.      KOH

c.       NaBr                    

d.      NaBrO

e.       H₂O

20.  From the redox reactions below, there is a reaction that classified as disproportionation or autoredox. This reaction is ….

a.       Na + Cl₂ à NaCl

b.      Cl₂ + NaI à NaCl + I₂

c.       I₂ + NaOH à NaI + NaIO₃        

d.      MnO₂+HClàMnCl₂+ Cl₂ + H₂O

e.       Na₂S₂O₃ + HCl àNaCl+S + SO₂ + H₂O

21.  The correct disproporsionation is …..

a.       MnO₂ à MnSO₄

b.      Cl₂ à Cl^- + ClO^-               

c.       Br^- + BrO₃^- à Br₂

d.      H⁺ + OH^- à H₂O

e.       MnO₄^- à Mn²⁺

22.  The symbol for the element cooper is Cu. The formula of cooper(I) oxide is …….

            a. CuO

b. Cu₂O

c. CuO₂          

d. CuO₃

            e. Cu₂O₂

23.  The name of Fe₂(SO₄)₃ and PbO₂ are ….

a.       iron sulfate and plumbum oxide

b.      iron(II) sulfate and plumbum oxide

c.       iron(II) sulfate and plumbum(I) oxide

d.      iron(III) sulfate and plumbum(II) oxide

e.       iron(III) sulfate and plumbum(IV) oxide